The mechanism of room temperature catalytic C–H dissociation and oxygenation of formaldehyde over nano-zirconia phase-junction

The room temperature catalytic efficiency of formaldehyde (HCHO) is determined by interfacial electrons transfer properties, gas adsorption configuration and reactivity of catalysts. The phase-junctions with lattice planes of high matching degree and abundant active sites may do better in the above three aspects than traditional catalysts and their heterojunctions. In this work, tetragonal-monoclinic nano-zirconia (ZrO₂) phase-junctions (TMZ) were synthesized for the first time. The highest conversion efficiency of HCHO into CO₂ was around 81% at 25 °C exceeded the value for pure ZrO₂. Density functional theory calculations and in-situ diffuse reflectance infrared Fourier transform spectroscopy measurements revealed that the adsorption enhancement of rich zirconium sites and single electron activation at TMZ interface caused C–H dissociation of HCHO and hydrogenation of O₂ (D–H), significantly lowering the activation barrier of catalytic oxidation of HCHO. Our findings can facilitate further design of more active catalyst for room temperature removal of HCHO.